It seems the Moto E was chosen just because it's a current phone that was cheap to buy.

Anyone think a Project Ara phone could be an option? http://www.projectara.com/

I like the idea of buying one configured as a Wi-Fi phone with no baseband or GPS module and with the right secure communication app could be "secure" enough. Maybe someone could see a market for a "open" baseband module for it and make one?